Femtosecond ultraviolet laser absorption spectroscopy for simultaneous measurements of temperature and OH concentration

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Timothy Y. Chen
  • Hongtao Zhong
  • Ying Lin
  • Ziyu Wang
  • Yiguang Ju

Detail(s)

Original languageEnglish
Article number201103
Journal / PublicationApplied Physics Letters
Volume120
Issue number20
Online published16 May 2022
Publication statusPublished - 16 May 2022
Externally publishedYes

Abstract

This Letter reports a femtosecond ultraviolet laser absorption spectroscopy (fs-UV-LAS) for simultaneous in situ measurements of temperature and species. This fs-UV-LAS technique was demonstrated based on X2Π-A2Σ+ transitions of OH radicals near 308 nm generated in low temperature plasmas and flames. The fs-UV-LAS technique has revealed three major diagnostic benefits. First, a series of absorption features within a spectral bandwidth of ∼3.2 nm near 308 nm were simultaneously measured and then enabled simultaneous multi-parameter measurements with enhanced accuracy. The results show that the temperature and OH concentration could be measured with accuracy enhanced by 29-88% and 58-91%, respectively, compared to those obtained with past two-narrow-line absorption methods. Second, an ultrafast time resolution of ∼120 picoseconds was accomplished for the measurements. Third, due to the large OH X2Π-A2Σ+ transitions in the UV range, a simple single-pass absorption with a 3-cm path length was allowed for measurements in plasmas with low OH number density down to ∼2 × 1013 cm-3. Also due to the large OH UV transitions, single-shot fs absorption measurements were accomplished in flames, which was expected to offer more insights into chemically reactive flow dynamics. © 2022 Author(s).

Citation Format(s)

Femtosecond ultraviolet laser absorption spectroscopy for simultaneous measurements of temperature and OH concentration. / Liu, Ning; Chen, Timothy Y.; Zhong, Hongtao et al.
In: Applied Physics Letters, Vol. 120, No. 20, 201103, 16.05.2022.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review